EP0939269A1 - Heat-fusion coil fitting incorporating a shrink sleeve and a fabrication process for the same - Google Patents

Heat-fusion coil fitting incorporating a shrink sleeve and a fabrication process for the same Download PDF

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Publication number
EP0939269A1
EP0939269A1 EP99103387A EP99103387A EP0939269A1 EP 0939269 A1 EP0939269 A1 EP 0939269A1 EP 99103387 A EP99103387 A EP 99103387A EP 99103387 A EP99103387 A EP 99103387A EP 0939269 A1 EP0939269 A1 EP 0939269A1
Authority
EP
European Patent Office
Prior art keywords
fitting
heating
heating coil
pipe
wall
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP99103387A
Other languages
German (de)
French (fr)
Other versions
EP0939269B1 (en
Inventor
Bernd Merle
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Individual
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Individual
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Filing date
Publication date
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Publication of EP0939269A1 publication Critical patent/EP0939269A1/en
Application granted granted Critical
Publication of EP0939269B1 publication Critical patent/EP0939269B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D23/00—Producing tubular articles
    • B29D23/001—Pipes; Pipe joints
    • B29D23/003—Pipe joints, e.g. straight joints
    • B29D23/005—Pipe joints, e.g. straight joints provided with electrical wiring
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C61/00—Shaping by liberation of internal stresses; Making preforms having internal stresses; Apparatus therefor
    • B29C61/06—Making preforms having internal stresses, e.g. plastic memory
    • B29C61/0608—Making preforms having internal stresses, e.g. plastic memory characterised by the configuration or structure of the preforms
    • B29C61/0616—Making preforms having internal stresses, e.g. plastic memory characterised by the configuration or structure of the preforms layered or partially layered preforms, e.g. preforms with layers of adhesive or sealing compositions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C61/00—Shaping by liberation of internal stresses; Making preforms having internal stresses; Apparatus therefor
    • B29C61/06—Making preforms having internal stresses, e.g. plastic memory
    • B29C61/0608—Making preforms having internal stresses, e.g. plastic memory characterised by the configuration or structure of the preforms
    • B29C61/0625—Preforms comprising incorporated or associated heating means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3404—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint
    • B29C65/342—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint comprising at least a single wire, e.g. in the form of a winding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3404—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint
    • B29C65/3464—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint characterised by the cross-section of said heated elements which remain in the joint or by the cross-section of their coating, e.g. being triangular
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3472—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint
    • B29C65/3476—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint being metallic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/66—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by liberation of internal stresses, e.g. shrinking of one of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112—Single lapped joints
    • B29C66/1122—Single lap to lap joints, i.e. overlap joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/114—Single butt joints
    • B29C66/1142—Single butt to butt joints
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/347—General aspects dealing with the joint area or with the area to be joined using particular temperature distributions or gradients; using particular heat distributions or gradients
    • B29C66/3472—General aspects dealing with the joint area or with the area to be joined using particular temperature distributions or gradients; using particular heat distributions or gradients in the plane of the joint, e.g. along the joint line in the plane of the joint or perpendicular to the joint line in the plane of the joint
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5221—Joining tubular articles for forming coaxial connections, i.e. the tubular articles to be joined forming a zero angle relative to each other
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5229—Joining tubular articles involving the use of a socket
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/73—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/737—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the state of the material of the parts to be joined
    • B29C66/7371—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the state of the material of the parts to be joined oriented or heat-shrinkable
    • B29C66/73715—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the state of the material of the parts to be joined oriented or heat-shrinkable heat-shrinkable
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L47/00—Connecting arrangements or other fittings specially adapted to be made of plastics or to be used with pipes made of plastics
    • F16L47/02—Welded joints; Adhesive joints
    • F16L47/03—Welded joints with an electrical resistance incorporated in the joint

Definitions

  • the invention relates to a heating coil fitting according to the preamble of the claim 1 and a manufacturing method for such a fitting according to the preamble of Claim 10.
  • Such heating coil fittings are used for the tight connection of at least two Installation components, such as two plastic pipes.
  • the fitting pipe of the heating coil fitting also made of plastic, points a heating coil arranged inside it, which over two to the outside guided connecting lines can be connected to an electrical energy source.
  • the Fitting pipe Around to connect two plastic pipes tightly together, these are in the Fitting pipe inserted, which has an inner diameter that is slightly larger than the outer diameter of the two pipes to be connected is. Then an electric current is fed to the heating coil, with a Part of the energy supplied due to the electrical inherent in the heating coil Resistance is converted into heat. This slowly penetrates from starting from the heating coil, the plastic materials of the pipes and fittings.
  • the Pipe wall is constructed from two tubular layers. Here is on the outer peripheral side the first tubular layer coaxially the second tubular layer arranged. Between the two tubular layers, it is helical running heating wire provided.
  • the inner, first layer is off made of a thermoplastic material.
  • the second layer of the fitting made of a thermosetting material.
  • the installation components to be connected with this known heating coil fitting are also built up in two layers, with the material on the inside, first layer of the installation components of the external, second layer of the Heating coil fittings and the external, second layer of the installation components of the corresponds to the inner, first layer of the heating coil fitting.
  • the outside ⁇ second layer of the installation components and the inner, first layer of the Heating coil fittings are the good ones due to their thermoplastic material Material connection between the individual components safe during welding.
  • the inner, first layer of the installation components and the external, second layer of the heating coil fitting has sufficient dimensional stability guarantee. Therefore, the last-mentioned locations are allowed during the connection process is not subject to any change in shape, otherwise a tight connection is not guaranteed. Therefore, in the case of relatively large gaps between those to be connected Components have the same problems of insufficient contact between the parts and the lack of joining pressure, as already mentioned above in Connection with the heating coil fittings known from practice explained have been.
  • a heating coil fitting emerges from European patent application 0 378 406 with a two-layer structure, the inner layer from a non-networked and the external layer from a networked Polyolefin exists.
  • the non-networked, inner layer is said to be a better one Connection between the material of this layer and the external material of the installation component or components. A measure to eliminate Dimensional tolerances are not discussed in this document.
  • the inhomogeneous structure of the heating coil fitting is achieved in that the subject to the shrinking process second material is embedded in the non-shrinking, first material.
  • the pipe wall of the fitting pipe has a sandwich structure in which at least one first, preferably tubular layer made of the first material and at least one second, also preferably tubular, layer from the second Material is provided. Of course, several layers from the first material and / or the second material.
  • the first layer made of the first material is concentrically surrounded by the second layer of the second material.
  • the fitting pipe has at least one Kernmantel that the heating element, for example in the form of a heating coil picks up and that of the first material, preferably one when heated at least plastically plastic and there is at least one outer jacket contains, which concentrically surrounds the kernmantel and that from the second Material, preferably consists of a thermo-shrinking material.
  • the heating element with the formation of in the longitudinal direction of the fitting pipe provided, unheated zones inside the fitting pipe is arranged.
  • these unheated or cold zones on the both ends of the fitting pipe and / or in the middle of the fitting pipe be provided.
  • thermoplastic such as, for example, can be used for the first material Polyethylene, cross-linked polyethylene, polypropylene, etc. are provided, whereas for the second material in particular a thermo-shrinking material, as is known for example from a shrink tube, or for example a PU, a plastic with a memory effect, etc. can be used.
  • any material can be used that a sufficiently high electrical resistance for implementation sufficient for a welding process of the supplied electrical energy in thermal energy.
  • the heating conductor consist of a copper alloy. It would also be for the heating conductor as material copper, nickel alloys, maganine, constantan, conductive plastics etc. can be used.
  • the Heating element used heating conductor is provided with a cross-sectional surface shape
  • the Expansion in the direction of the central longitudinal axis of the fitting pipe is smaller than in radial direction is because the heat has the better thermal conductivity of the Heating conductor penetrates faster or is generated there directly.
  • a quick, in particular gas or liquid-tight welding of the parts to be connected Installation components, fittings, etc. can be achieved because of the heating conductor penetrates the fitting pipe accordingly far in its radial direction.
  • the radial expansion of the cross-sectional area of the heating conductor can be arbitrary be selected as long as the above condition is met. It has found to be advantageous that the radial expansion of the heating conductor should be at least 30% of the radial wall thickness of the fitting. This will ensured that the thermal energy quickly into the material of the pipe wall of the Heating coil fittings is introduced.
  • any cross-sectional area geometry can be used for the heating conductor can be selected as long as the above condition is met. It turned out to be proven to be particularly advantageous if the cross-sectional area is at least approximately is rectangular, the narrow or broad side of the rectangle essentially parallel to the central longitudinal axis of the fitting pipe and the long side in the runs essentially in the radial direction of the fitting pipe.
  • the ratio of height to width of the rectangular heating conductor is at least 5: 2.
  • a particularly good connection is achieved in that the heating conductor of the preferably formed by a heating coil flush with the Completes the inner circumferential surface of the fitting pipe.
  • Shows the cross-sectional area of the heating element has a rectangular shape, so that in particular also a good warming of the two installation components to be connected achieved because in contrast to the known Schuchtlfittingen with a a flat cross-section of the heating spiral conductor Contact between the heating conductor and the respective installation component is reached.
  • the slope of the helically wound heating conductor can vary depending on the Ratios can be chosen arbitrarily. It turned out to be advantageous if the slope is at least the height of the heating conductor or its radial Expansion corresponds.
  • the heating conductor is preferably on its from the Inner circumferential surface of the fitting pipe with the notch side is provided.
  • the notches can also be made on the Inner circumferential surface of the fitting pipe-facing side or in any position be provided on the heating conductor. Furthermore, these notches in Longitudinal direction of the heating conductor in a constant as well as not constant distance from each other.
  • the present invention is not limited to the use of heating coil fittings for connecting two tubes are provided.
  • it can also be used for T-shaped heating coil fittings, designed to connect three pipes, etc. be used.
  • the heating coil fitting according to the invention can also be used in such a way that, for example, initially only a plastic tube inserted and welded to the heating coil fitting. The other Installation component or the other fitting can then be replaced later plastic pipe to be inserted, a screwable into the free end of the fitting pipe Valve made of metal or a valve made of plastic, a hose, etc. be.
  • the Heating coil fitting has two independently controllable heating elements, so that with the one heating element the plastic tube initially introduced the heating coil fitting can be welded, whereas the second heating element then to connect the other installation component with the heating coil fitting serves.
  • the number to be provided in the heating coil fitting Heating elements not determined by this; it is for any purpose a corresponding number of heating elements possible.
  • the above task is characterized by features of Claim 10 solved.
  • at least one surrounding the core jacket Outer jacket is provided, which at least shrinks when heated Material is produced and which has an inner diameter which is smaller than the outer diameter of the core jacket, and that for mounting the Outer jacket on the core jacket the inner diameter of the outer jacket is expanded. Due to the shrinking properties of the material of the outer jacket The outer jacket then fixes itself on the core jacket.
  • FIGS. 1 and 2 each show a part according to the invention in a partial longitudinal cross section Kirschlfitting 10 reproduced. Its central longitudinal or symmetrical longitudinal axis M runs horizontally, based on FIGS. 1 and 2.
  • FIGS. 1 and 2 are identical components with the same reference numerals.
  • the heating coil fitting 10 of FIG. 1 has a fitting pipe 20 and a heating element 30 preferably in the form of a heating coil.
  • the one defining the fitting pipe 20 Tube wall 22 comprises a core jacket 24 and forming a first tubular layer an outer jacket 26 forming a second tubular layer, which is the core jacket 24 concentrically surrounds.
  • the outer jacket 26 lies flat on the Kernmantel 24 on.
  • the outer jacket 26 includes the core jacket 24 flush at the end faces. Basically, there is also the possibility that the outer jacket 26 has a longer or shorter axial length has as the core jacket 24.
  • the core jacket 24 consists of an at least plasticizing when heated or softening material, preferably made of a thermoplastic Plastic.
  • the core is preferably one Copper alloy manufactured and in this embodiment with a round Cross section of heating conductor 32 of heating coil 30 arranged in such a way that it is in the vicinity of the inner circumferential wall 20a of the fitting pipe 20 or Core shell 24 is located inside the core shell 24.
  • the heating conductor 32 is spirally wound and with not shown connection ends with a electrical energy source connectable.
  • the heating conductor 32 of the heating coil 30 is arranged in the interior of the core jacket 24 in such a way that two heating areas H 1 , H 2 and three unheated or “cold” zones Z 1 , Z 2 , Z 3 are present are.
  • the heating conductor 32 of the heating coil 30 has two areas H 1 , H 2 , in each of which there are eleven windings, these two areas H 1 , H 2 being separated from one another in the axial direction of the heating coil fitting 10 by an unheated zone Z 2 .
  • Unheated zones Z 1 , Z 3 are also provided on the two ends 20b, 20c of the fitting pipe 20, which zones extend axially from the respective end 20b, 20c into the interior of the fitting pipe 20 or the core shell 24.
  • the outer jacket 26 of the heating coil fitting 10 consists of a shrinking Material such as VPE, a plastic with memory effect, etc.
  • a shrinking Material such as VPE, a plastic with memory effect, etc.
  • the outer jacket 26 is heated by the Heating coil 30 shrinks the material of the outer jacket 26 and thereby exercises a pressure on the core jacket 24 and thus on the two together connecting, but not shown in Figure 1, preferably made of pipes thermoplastic plastic.
  • the outer jacket 26 applied to the core jacket 24.
  • the outer jacket 26 an inner diameter that is smaller than the outer diameter of the Core sheath 24.
  • the outer jacket 26 can be on the outer peripheral surface of the core jacket 24 be postponed. Due to the shrink properties of the outer jacket 26 the outer jacket 26 then sits firmly on the core jacket 24.
  • FIG 2 is another embodiment of an inventive Heater coil fittings 10 shown. This heating coil fitting is divided into a core jacket and in an outer jacket for the purpose of illustrating the no further inventive idea.
  • the heating conductor 32 of the heating coil 30 has one rectangular cross-section or a rectangular cross-sectional area A, the cross section in a the central longitudinal axis M of the fitting pipe 20 containing plane.
  • the width of the rectangular heating conductor 32 i.e. its length in the axial direction of the fitting pipe 20 is less than its length in radial direction of the tube 20.
  • the heating conductor 32 penetrates much deeper into the material of the fitting pipe 20 a than this with a fitting pipe with the same wall thickness and a heating conductor with a round cross section is the case, as a simple comparison of Figures 1 and 2 shows. It has proven to be advantageous if the radial expansion of the Edelleiters 32 or the height of the cross-sectional area A at least 30% of radial wall thickness of the tube wall 22 is. Because of the rectangular The cross section of the heating conductor 32 is also the distance between two successive ones Edelleiterchtln constant, so that, in contrast to the state of Technology with a heating conductor having a circular cross section, the Intermediate areas between two successive heating conductor coils be heated evenly.
  • the distance or slope of the helical Heating conductor 32 preferably corresponds at least to the length of the radial one Extension of the heating conductor 32.
  • FIG 3 is a side view of, for example, made of a copper alloy produced heating conductor 32 of the heating coil fitting 30 according to the invention reproduced.
  • the heating conductor 32 is uniform Distances on its from the inner peripheral surface 22 of the fitting pipe 20th technological side with equally spaced notches 34 provided. These notches 34 allow, inter alia, a spiral Winding the heating conductor 32 to form a heating coil 30 without tearing it.
  • the invention closes Bankhauslfitting 10 of the heating conductor 32 of the heating coil 30 flush with the Inner circumferential surface 20a of the fitting pipe 20. Because of the rectangular shape Cross section of the heating conductor 32 of the heating coil 30 is also in In contrast to a heating conductor with a round cross section, a better one Warming of the two pipes K1, K2 to be connected is achieved because the heating conductor 32 with its broad side in each case on those to be connected to one another Pipes "stands up". In contrast, a heating conductor with a circular Cross section, as is often the case in the prior art, only a line contact between the heating conductor and the two pipes to be connected K1, K2 possible.
  • the heating coil 30 is arranged in the fitting pipe 20 in order to prevent warm plastic from flowing out of the heating coil fitting 10, so that a total of three unheated zones or "cold" zones Z 1 , Z 2 , Z 3 between the two heated zones H 1 , H 2 , each comprising seven windings or coils.
  • the unheated zones Z 1 , Z 3 extend axially inward from the front ends 20b, 20c of the fitting pipe 20.
  • the third "cold" zone Z 2 lies in the middle of the fitting pipe 20.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Branch Pipes, Bends, And The Like (AREA)
  • Resistance Heating (AREA)

Abstract

The wall (22) of the tubular fitting (20) includes one or more heating coils (30) and comprises a concentric twin wall structure, the inner wall being made of a plasticizable material (24) and the outer wall of another material (26) which shrinks when heated. An Independent claim is made for a method for manufacturing the heating coil fitting in which an outer cover of shrinkable material (26) is produced with an internal diameter smaller than the outer diameter of the inner cover layer (24) and which is expanded to fit it onto the inner cover. Preferred Features: The heating element (30) is arranged inside the fitting (20) and forms unheated zones (Z1,Z2,Z3) inside the latter. In a design variation using a heating wire with a rectangular cross-section the radial length of the heating wire is NOTLESS 30% of the tubular wall thickness. The ratio of radial to axial lengths of the cross-section is 5:2 and the pitch of the coiled heating wire (32) corresponds to the radial length of the heating wire (32).

Description

Die Erfindung betrifft ein Heizwendelfitting gemäß dem Oberbegriff des Anspruchs 1 sowie ein Herstellverfahren für ein derartiges Fitting gemäß dem Oberbegriff des Anspruchs 10.The invention relates to a heating coil fitting according to the preamble of the claim 1 and a manufacturing method for such a fitting according to the preamble of Claim 10.

Derartige Heizwendelfittinge werden zum dichten Verbinden wenigstens zweier Installationsbauteile, wie beispielsweise zweier Rohre aus Kunststoff eingesetzt. Hierzu weist das ebenfalls aus Kunststoff hergestellte Fittingrohr des Heizwendelfittings eine in seinem Inneren angeordnete Heizwendel auf, die über zwei nach außen geführte Anschlußleitungen mit einer elektrischen Energiequelle verbindbar ist. Um zwei Kunststoffrohre miteinander dicht zu verbinden, werden diese in das Fittingrohr eingeschoben, das einen Innendurchmesser aufweist, der geringfügig größer als der Außendurchmesser der beiden miteinander zu verbindenden Rohre ist. Anschließend wird ein elektrischer Strom der Heizwendel zugeführt, wobei ein Teil der zugeführten Energie infolge des der Heizwendel innewohnenden elektrischen Widerstandes in Wärme umgesetzt wird. Diese durchdringt langsam, von der Heizwendel ausgehend, die Kunststoffmaterialen der Rohre und des Fittings. Bei Überschreiten des Erweichungspunktes bzw. des Schmelzbereiches plastifizieren bzw. erweichen diese Materialien und fließen ineinander. Beim Erkalten härten sie dann als gas- bzw. flüssigdichte Verbindung zwischen den beiden Rohren und dem Fitting aus. Für diesen Vorgang wird auch der Begriff "Heizwendelschweißen" bzw. "Schweißen" verwendet.Such heating coil fittings are used for the tight connection of at least two Installation components, such as two plastic pipes. For this purpose, the fitting pipe of the heating coil fitting, also made of plastic, points a heating coil arranged inside it, which over two to the outside guided connecting lines can be connected to an electrical energy source. Around to connect two plastic pipes tightly together, these are in the Fitting pipe inserted, which has an inner diameter that is slightly larger than the outer diameter of the two pipes to be connected is. Then an electric current is fed to the heating coil, with a Part of the energy supplied due to the electrical inherent in the heating coil Resistance is converted into heat. This slowly penetrates from starting from the heating coil, the plastic materials of the pipes and fittings. At Plasticize if the softening point or melting range is exceeded or soften these materials and flow into one another. They harden when they cool down then as a gas or liquid-tight connection between the two pipes and the Fitting out. For this process, the term "electrofusion welding" or "Welding" used.

Beim dichten Verbinden von Installationsbauteilen oder Armaturen, von denen wenigstens eines aus Kunststoff ist, unter Verwendung eines Heizwendelfittings sind verschiedene Gesichtspunkte zu berücksichtigen, die teilweise gegenläufig sind. Zunächst ist zu beachten, daß die Erweichungs- bzw. Schmelztemperatur für ein genügend großes Volumen an der Verbindungsstelle von den beispielsweise beiden Kunststoffrohren und dem Fitting überschritten wird. Mit anderen Worten muß eine ausreichende Durchwärmung an den beiden Rohren und dem Fitting vorhanden sein. Eine zu geringe Durchwärmung hat mangelnde Stabilität nach der Aushärtung, eine zu große Durchwärmung eine Deformation während der Aufwärm- bzw. Aufheizphase zur Folge. Außerdem darf eine bestimmte Temperatur oberhalb der Erweichungs- bzw. Schmelztemperatur an keinem Punkt des bzw. der Materialien überschritten werden, sonst tritt eine chemische Alterung bzw. Versprödung des bzw. der Kunststoffmaterialien ein. Schließlich muß in der Verbindungs- bzw. Schweißzone während des Schweißvorgangs ein Fügedruck aufgebaut werden, um eine ausreichende Vernetzung bzw. Durchdringung des Materials der Kunststoffrohre und des Fittings zu gewährleisten.When tightly connecting installation components or fittings, of which at least one is made of plastic, using a heating coil fitting There are various aspects to consider, some of which are contradictory are. First of all, it should be noted that the softening or melting temperature for a sufficiently large volume at the junction of, for example both plastic pipes and the fitting is exceeded. In other words there must be sufficient heating on the two pipes and the fitting to be available. Too little warming has poor stability after Curing, too much warming a deformation during the Warming up or heating up phase. In addition, a certain temperature at no point above the softening or melting temperature Materials are exceeded, otherwise chemical aging or Embrittlement of the plastic material (s). Finally, in the Joining or welding zone during the welding process a joining pressure be built up to ensure sufficient networking or penetration of the To ensure the material of the plastic pipes and fittings.

Bei den in der Praxis bekannten Heizwendelfittingen wird der vorstehend erwähnte Fügedruck ausschließlich durch die thermische Ausdehnung des Kunststoffmaterials und durch parasitäres Schrumpfen der spritzgegossenen Fittingrohre erreicht. Hierbei hat es sich als nachteilig erwiesen, daß die Spaltweite zwischen beispielsweise zwei miteinander zu verbindenden Kunststoffrohren und dem Heizwendelfitting vor dem Verschweißen nicht klar definiert ist. Es kann hier insbesondere bei großen Heizwendelfittingen zu Spalten von mehreren Millimetern kommen. Dies kann zu einem unzureichenden thermischen Kontakt zwischen den beiden miteinander zu verbindenden Installationsbauteilen und dem Heizwendelfitting sowie zu einem mangelnden Fügedruck führen, was zwangsläufig zu undichten Verbindungen führt.In the heating coil fittings known in practice, the one mentioned above Joining pressure only due to the thermal expansion of the plastic material and achieved by parasitic shrinkage of the injection molded fitting pipes. It has proven disadvantageous here that the gap width between, for example two plastic pipes to be connected and the heating coil fitting is not clearly defined before welding. It can be particularly useful here large heating coil fittings lead to gaps of several millimeters. This can cause insufficient thermal contact between the two installation components to be connected and the heating coil fitting as well as lead to a lack of joining pressure, which inevitably leads to leakage Leads.

Aus dem US-Patent 4,972,184 geht ein Heizwendelfitting hervor, dessen Rohrwand aus zwei rohrartigen Lagen aufgebaut ist. Hierbei ist an der Außenumfangsseite der ersten rohrartigen Lage koaxial die zweite rohrartige Lage angeordnet. Zwischen den beiden rohrartigen Lagen ist der wendelförmig verlaufende Heizdraht vorgesehen. Die innenliegende, erste Lage ist dabei aus einem thermoplastischen Material hergestellt. Demgegenüber ist die außenliegende, zweite Lage des Fittings aus einem duroplastischen Material gefertigt.From US Pat. No. 4,972,184 a heating coil fitting emerges, the Pipe wall is constructed from two tubular layers. Here is on the outer peripheral side the first tubular layer coaxially the second tubular layer arranged. Between the two tubular layers, it is helical running heating wire provided. The inner, first layer is off made of a thermoplastic material. In contrast, the second layer of the fitting made of a thermosetting material.

Die mit diesem bekannten Heizwendelfitting zu verbindenden Installationsbauteile sind ebenfalls zweilagig aufgebaut, wobei hinsichtlich des Materials die innenliegende, erste Lage der Installationsbauteile der außenliegenden, zweiten Lage des Heizwendelfittings und die außenliegende, zweite Lage der Installationsbauteile der innenliegenden, ersten Lage des Heizwendelfittings entspricht. Die außenliegende` zweite Lage der Installationsbauteile sowie die innenliegende, erste Lage des Heizwendelfittings stellen infolge ihres thermoplastischen Materials die gute Materialverbindung zwischen den einzelnen Bauteilen beim Schweißen sicher. Demgegenüber sollen die innenliegende, erste Lage der Installationsbauteile sowie die außenliegende, zweite Lage des Heizwendelfittings eine ausreichende Formstabilität gewährleisten. Daher dürfen gerade die zuletzt genannten Lagen während des Verbindungsvorgangs keiner Formänderung unterliegen, da andernfalls eine dichte Verbindung nicht gewährleistet ist. Daher besteht aber hier im Falle von verhältnismäßig großen Spalten zwischen den miteinander zu verbindenden Bauteilen die gleichen Probleme hinsichtlich des unzureichenden Kontakts zwischen den Teilen und des mangelenden Fügedrucks, wie sie bereits vorstehend im Zusammenhang mit den aus der Praxis bekannten Heizwendelfittingen erläutert worden sind.The installation components to be connected with this known heating coil fitting are also built up in two layers, with the material on the inside, first layer of the installation components of the external, second layer of the Heating coil fittings and the external, second layer of the installation components of the corresponds to the inner, first layer of the heating coil fitting. The outside` second layer of the installation components and the inner, first layer of the Heating coil fittings are the good ones due to their thermoplastic material Material connection between the individual components safe during welding. In contrast, the inner, first layer of the installation components and the external, second layer of the heating coil fitting has sufficient dimensional stability guarantee. Therefore, the last-mentioned locations are allowed during the connection process is not subject to any change in shape, otherwise a tight connection is not guaranteed. Therefore, in the case of relatively large gaps between those to be connected Components have the same problems of insufficient contact between the parts and the lack of joining pressure, as already mentioned above in Connection with the heating coil fittings known from practice explained have been.

Weiterhin geht aus der europäischen Patentanmeldung 0 378 406 ein Heizwendelfitting mit einem zweilagigen Aufbau hervor, wobei die innenliegende Lage aus einem nichtvernetzten und die außenliegende Lage aus einem vernetzten Polyolefin besteht. Die nichtvernetzte, innenliegende Lage soll eine bessere Verbindung zwischen dem Material dieser Lage und dem außenliegenden Material des oder der Installationsbauteile sicherstellen. Eine Maßnahme zur Beseitigung von Maßtoleranzen ist in dieser Entgegenhaltung nicht diskutiert.Furthermore, a heating coil fitting emerges from European patent application 0 378 406 with a two-layer structure, the inner layer from a non-networked and the external layer from a networked Polyolefin exists. The non-networked, inner layer is said to be a better one Connection between the material of this layer and the external material of the installation component or components. A measure to eliminate Dimensional tolerances are not discussed in this document.

Es ist Aufgabe der vorliegenden Erfindung, ein Heizwendelfitting sowie ein Herstellverfahren hierfür zu schaffen, die unabhängig von dem Durchmesser der zu verbindenden Rohre und dem Fitting eine dichte Verbindung ermöglichen.It is an object of the present invention, a heating coil fitting and a To create manufacturing processes for this, regardless of the diameter of the connecting pipes and the fitting allow a tight connection.

Die vorstehende Aufgabe wird hinsichtlich des Heizwendelfittings durch die Merkmale des Anspruchs 1 gelöst. Durch die inhomogene Gestaltung des Fittingrohres aus einem ersten Material, das bei Erwärmung zumindest plastifiziert bzw. erweicht, vorzugsweise schmilzt, und einem zweiten Material, das vorzugsweise zumindest bei Erwärmung einem Schrumpfvorgang unterliegt, wird zum einen die Durchdringung bzw. das Verschmelzen der miteinander zu verbindenden Installationsbauteile sowie des Heizwendelfittings unterstützt und zum anderen ein ausreichend hoher Fügedruck durch den Schrumpfvorgang des zweiten Materials erzielt. Daher kann selbst bei Heizwendelfittingen mit einem großen Durchmesser und/oder bei Verbindungen mit einem großen Spalt zwischen der Innenumfangswand des Heizwendelfittings und den Außenumfangswänden der beiden miteinander zu verbindenden Installationsbauteile eine sichere und dichte Verbindung erreicht werden. In diesem Zusammenhang ist noch zu bemerken, daß im Falle eines Heizwendelfittings, mit dem beispielsweise ein Kunststoffrohr mit einem Ventil aus Metall oder dgl. verbunden werden soll, der vorstehend geschilderte inhomogene Aufbau des Heizwendelfittings sich auch nur über einen Abschnitt in Längsrichtung des Heizwendelfittings erstrecken kann, nämlich über denjenigen Bereich, in dem das Kunststoffrohr aufgenommen ist.The above task is accomplished by the Features of claim 1 solved. Due to the inhomogeneous design of the Fitting pipe made of a first material that at least plasticizes when heated or softens, preferably melts, and a second material, which preferably undergoes a shrinking process at least when heated a penetration or fusion of those to be connected Installation components and the heating coil fittings supported and on the other sufficiently high joining pressure due to the shrinking process of the second material achieved. Therefore, even with heating coil fittings with a large diameter and / or for connections with a large gap between the inner peripheral wall of the heating coil fitting and the outer peripheral walls of the two together installation components to be connected a secure and tight connection can be achieved. In this connection it should be noted that in the case a heating coil fitting with which, for example, a plastic pipe with a Valve made of metal or the like. To be connected, the above inhomogeneous structure of the heating coil fitting is also only over a section in Can extend longitudinally of the heating coil fitting, namely over that Area in which the plastic pipe is accommodated.

Grundsätzlich besteht die Möglichkeit, daß der inhomogene Aufbau des Heizwendelfittings dadurch erzielt wird, daß das dem Schrumpfvorgang unterliegende, zweite Material in dem nicht schrumpfenden, ersten Material eingelagert ist. Eine weitere vorteilhafte Ausgestaltung der vorliegenden Erfindung besteht darin, daß die Rohrwand des Fittingrohres einen Sandwichaufbau aufweist, bei dem mindestens eine erste, vorzugsweise rohrartige Lage aus dem ersten Material und wenigstens eine zweite, ebenfalls vorzugsweise rohrartige Lage aus dem zweiten Material vorgesehen ist. Selbstverständlich können auch mehrere Lagen aus dem ersten Material und/oder dem zweiten Material vorhanden sein.Basically, there is the possibility that the inhomogeneous structure of the heating coil fitting is achieved in that the subject to the shrinking process second material is embedded in the non-shrinking, first material. A Another advantageous embodiment of the present invention is that the pipe wall of the fitting pipe has a sandwich structure in which at least one first, preferably tubular layer made of the first material and at least one second, also preferably tubular, layer from the second Material is provided. Of course, several layers from the first material and / or the second material.

Hierbei kann vorgesehen sein, daß die erste Lage aus dem ersten Material konzentrisch von der zweiten Lage des zweiten Materials umgeben ist. Dies kann beispielsweise dadurch realisiert werden, daß das Fittingrohr wenigstens einen Kernmantel, der das Heizelement, beispielsweise in Form einer Heizwendel aufnimmt und der aus dem ersten Material, vorzugsweise aus einem bei Erwärmung zumindest plastisch werden Kunststoff besteht, und mindestens einen Außenmantel enthält, der den Kernmantel konzentrisch umgibt und der aus dem zweiten Material, vorzugsweise aus einem thermoschrumpfenden Material besteht.It can be provided that the first layer made of the first material is concentrically surrounded by the second layer of the second material. This can can be realized, for example, in that the fitting pipe has at least one Kernmantel that the heating element, for example in the form of a heating coil picks up and that of the first material, preferably one when heated at least plastically plastic and there is at least one outer jacket contains, which concentrically surrounds the kernmantel and that from the second Material, preferably consists of a thermo-shrinking material.

Damit beim Verschweißen der Installationsbauteile und dem Fitting ein Herauspressen von geschmolzenem Material aus dem Spalt zwischen dem Fittingrohr und den zu verbindenden Installationsbauteilen verhindert wird, kann weiterhin vorgesehen werden, daß das Heizelement unter Ausbildung von in Längsrichtung des Fittingrohres vorgesehenen, unbeheizten Zonen im Inneren des Fittingrohres angeordnet ist. Vorzugsweise können diese unbeheizten bzw. kalten Zonen an den beiden stirnseitigen Enden des Fittingrohres und/oder in der Mitte des Fittingrohres vorgesehen sein.So that it is pressed out when welding the installation components and the fitting of molten material from the gap between the fitting pipe and the installation components to be connected can still be prevented be provided that the heating element with the formation of in the longitudinal direction of the fitting pipe provided, unheated zones inside the fitting pipe is arranged. Preferably, these unheated or cold zones on the both ends of the fitting pipe and / or in the middle of the fitting pipe be provided.

Für das erste Material kann beispielsweise ein Thermoplast, wie zum Beispiel Polyethylen, vernetztes Polyethylen, Polypropylen usw. vorgesehen werden, wogegen für das zweite Material ein insbesondere thermoschrumpfendes Material, wie es beispielsweise von einem Schrumpfschlauch bekannt ist, oder zum Beispiel ein VPE, ein Kunststoff mit einem Memoryeffekt usw. eingesetzt werden kann.A thermoplastic such as, for example, can be used for the first material Polyethylene, cross-linked polyethylene, polypropylene, etc. are provided, whereas for the second material in particular a thermo-shrinking material, as is known for example from a shrink tube, or for example a PU, a plastic with a memory effect, etc. can be used.

Für den Heizleiter des Heizelements, das vorzugsweise durch eine Heizwendel gebildet ist, kann jedes Material eingesetzt werden, daß einen ausreichend hohen elektrischen Widerstand zur für einen Schweißvorgang ausreichenden Umsetzung der zugeführten elektrischen Energie in Wärmeenergie aufweist. Vorzugsweise kann der Heizleiter aus einer Kupferlegierung bestehen. Ebenfalls wäre für den Heizleiter als Material Kupfer, Nickellegierungen, Maganin, Konstantan, leitfähige Kunststoffe usw. einsetzbar.For the heating conductor of the heating element, preferably by means of a heating coil is formed, any material can be used that a sufficiently high electrical resistance for implementation sufficient for a welding process of the supplied electrical energy in thermal energy. Preferably can the heating conductor consist of a copper alloy. It would also be for the heating conductor as material copper, nickel alloys, maganine, constantan, conductive plastics etc. can be used.

Um eine bessere, insbesondere schnellere Durchwärmung des Heizwendelfittings zu erreichen, kann weiterhin vorgesehen sein, daß der für das Heizelement verwendete Heizleiter mit einer Querschnittsflächenform versehen ist, deren Ausdehnung in Richtung der Mittellängsachse des Fittingrohres kleiner als in radialer Richtung ist, da die Wärme über die bessere Wärmeleitfähigkeit des Heizleiters schneller in die Tiefe dringt oder dort direkt erzeugt wird. Insbesondere bei Fittingen mit großen Wandstärken bzw. großen Durchmessern kann hierdurch trotz des großen Durchmessers bzw. der großen Wandstärke ein schnelles, insbesondere gas- bzw. flüssigdichtes Verschweißen der miteinander zu verbindenden Installationsbauteile, Armaturen usw. erzielt werden, da der Heizleiter das Fittingrohr entsprechend weit in dessen radialer Richtung durchsetzt. Es besteht hierbei auch nicht die Gefahr, daß das Material in der Nähe der Innenumfangsfläche des Fittingrohres bereits einer chemischen Alterung ausgesetzt ist, während das sich in Richtung der Außenumfangsfläche daran anschließende Material noch nicht die zu einem optimalen Verbinden der Installationsbauteile notwendige Temperatur erreicht hat. Durch eine geeignete Wahl des Aspektverhältnisses, d.h. des Verhältnisses von Breite zu Höhe der besagten Querschnittsfläche des Heizleiters kann dieser in bezug auf optimale Durchwärmung und Stabilität optimiert werden. Dieser Gedanke sowie die hiermit verbundenen weiteren vorteilhaften Ausgestaltungen können auch unabhängig von dem inhomogenen Aufbau der Rohrwand bei Heizwendelfittingen vorteilhaft eingesetzt werden.For better, especially faster heating of the heating coil fittings To achieve, it can also be provided that for the heating element used heating conductor is provided with a cross-sectional surface shape, the Expansion in the direction of the central longitudinal axis of the fitting pipe is smaller than in radial direction is because the heat has the better thermal conductivity of the Heating conductor penetrates faster or is generated there directly. Especially this can result in fittings with large wall thicknesses or large diameters despite the large diameter or the large wall thickness, a quick, in particular gas or liquid-tight welding of the parts to be connected Installation components, fittings, etc. can be achieved because of the heating conductor penetrates the fitting pipe accordingly far in its radial direction. It there is also no risk that the material in the vicinity of the inner peripheral surface the fitting pipe is already exposed to chemical aging, while that adjoining it in the direction of the outer peripheral surface Material not yet to optimally connect the installation components has reached the necessary temperature. By a suitable choice of the aspect ratio, i.e. the ratio of width to height of said cross-sectional area of the heating conductor can this in terms of optimal warming and Stability can be optimized. This thought as well as the associated ones further advantageous embodiments can also be independent of the inhomogeneous structure of the tube wall is advantageously used in heating coil fittings become.

Die radiale Ausdehnung der Querschnittsfläche des Heizleiters kann beliebig gewählt werden, solange die vorstehend genannte Bedingung erfüllt ist. Es hat sich als vorteilhaft herausgestellt, daß die radiale Ausdehnung des Heizleiters mindestens 30 % der radialen Wanddicke des Fittings betragen soll. Hierdurch wird sichergestellt, daß die Wärmeenergie schnell in das Material der Rohrwand des Heizwendelfittings eingebracht wird.The radial expansion of the cross-sectional area of the heating conductor can be arbitrary be selected as long as the above condition is met. It has found to be advantageous that the radial expansion of the heating conductor should be at least 30% of the radial wall thickness of the fitting. This will ensured that the thermal energy quickly into the material of the pipe wall of the Heating coil fittings is introduced.

Grundsätzlich kann für den Heizleiter jede beliebige Querschnittsflächengeometrie gewählt werden, solange die vorstehende Bedingung erfüllt ist. Es hat sich als besonders vorteilhaft erwiesen, wenn die Querschnittsfläche zumindest annährend rechteckförmig ist, wobei die Schmal- bzw. Breitseite des Rechtecks im wesentlichen parallel zur Mittellängsachse des Fittingrohres und die Längsseite im wesentlichen in radialer Richtung des Fittingrohres verläuft.In principle, any cross-sectional area geometry can be used for the heating conductor can be selected as long as the above condition is met. It turned out to be proven to be particularly advantageous if the cross-sectional area is at least approximately is rectangular, the narrow or broad side of the rectangle essentially parallel to the central longitudinal axis of the fitting pipe and the long side in the runs essentially in the radial direction of the fitting pipe.

Bei einer rechteckförmigen Ausgestaltung des Heizleiters hat es sich als vorteilhaft erwiesen, wenn daß Verhältnis von Höhe zu Breite des rechteckförmigen Heizleiters mindestens 5 : 2 beträgt.With a rectangular configuration of the heating conductor, it has proven to be advantageous proved if the ratio of height to width of the rectangular heating conductor is at least 5: 2.

Eine besonders gute Verbindung wird dadurch erzielt, daß der Heizleiter des vorzugsweise durch eine Heizwendel gebildeten Heizelements bündig mit der Innenumfangsfläche des Fittingrohres abschließt. Weist dabei die Querschnittsfläche des Heizelements eine Rechteckform auf, so wird hierdurch insbesondere auch eine gute Durchwärmung der beiden miteinander zu verbindenen Installationsbauteile erreicht, da im Gegensatz zu den bekannten Heizwendelfittingen mit einem einen kreisförmigen Querschnitt besitzenden Heizwendelleiter eine flächige Berührung zwischen Heizleiter und dem jeweiligen Installationsbauteil erreicht wird. Bei den bekannten Heizwendelfittingen findet sich dort dagegen nur eine Linienberührung.A particularly good connection is achieved in that the heating conductor of the preferably formed by a heating coil flush with the Completes the inner circumferential surface of the fitting pipe. Shows the cross-sectional area of the heating element has a rectangular shape, so that in particular also a good warming of the two installation components to be connected achieved because in contrast to the known Heizwendelfittingen with a a flat cross-section of the heating spiral conductor Contact between the heating conductor and the respective installation component is reached. In the known Heizwendelfittingen, however, there is only one Line contact.

Die Steigung des wendelförmig gewickelten Heizleiters kann je nach den Verhältnissen beliebig gewählt werden. Es hat sich als vorteilhaft herausgestellt, wenn die Steigung mindestens der Höhe des Heizleiters bzw. seiner radialen Ausdehnung entspricht. The slope of the helically wound heating conductor can vary depending on the Ratios can be chosen arbitrarily. It turned out to be advantageous if the slope is at least the height of the heating conductor or its radial Expansion corresponds.

Je nach gewähltem Material für den Heizleiter des Heizelements kann es genügen, daß dieser beispielsweise einfach zu einer Heizwendel gewickelt wird. Um jedoch ein Reißen des Heizleiters beim Wickeln zu einer Wendel zu vermeiden, kann es weiterhin von Vorteil sein, wenn der Heizleiter vorzugsweise auf seiner von der Innenumfangsfläche des Fittingrohres wegweisenden Seite mit Einkerbungen versehen ist. Selbstverständlich können die Einkerbungen auch auf der zu der Innenumfangsfläche des Fittingrohres weisenden Seite oder in jeder beliebigen Lage an dem Heizleiter vorgesehen sein. Weiterhin können diese Einkerbungen in Längsrichtung des Heizleiters sowohl in einem konstanten als auch in einem nicht konstanten Abstand zueinander angeordnet sein.Depending on the material selected for the heating element of the heating element, it may be sufficient that this is simply wound into a heating coil, for example. However, to It can prevent the heating conductor from tearing when it is wound into a coil continue to be advantageous if the heating conductor is preferably on its from the Inner circumferential surface of the fitting pipe with the notch side is provided. Of course, the notches can also be made on the Inner circumferential surface of the fitting pipe-facing side or in any position be provided on the heating conductor. Furthermore, these notches in Longitudinal direction of the heating conductor in a constant as well as not constant distance from each other.

Grundsätzlich besteht die Möglichkeit, daß mehrere Heizelemente in einem Fittingrohr vorgesehen sind. Eine derartige Lösung bietet sich beispielsweise bei einem T-förmigen Fittingrohr an, welches beispielsweise zum Verbinden von drei Rohren eingesetzt werden kann. Ist das Fittingrohr lediglich zum Verbinden von beispielsweise zwei Kunststoffrohren vorgesehen, so ist es vorteilhaft, wenn sich ein Heizelement über die gesamte Axiallänge des Fittingrohres erstreckt.Basically, there is the possibility that several heating elements in one Fitting pipe are provided. Such a solution is available, for example a T-shaped fitting pipe, which can be used, for example, to connect three Pipes can be used. Is the fitting pipe only for connecting For example, two plastic pipes are provided, so it is advantageous if a heating element extends over the entire axial length of the fitting pipe.

Wie dies bereits vorstehend angesprochen wurde, ist die vorliegende Erfindung nicht auf den Einsatz von Heizwendelfittingen beschränkt, die zum Verbinden von zwei Rohren vorgesehen sind. Sie kann beispielsweise auch für T-förmige Heizwendelfittinge, die zum Verbinden von drei Rohren vorgesehen sind, usw. eingesetzt werden. Weiterhin kann das erfindungsgemäße Heizwendelfitting auch in der Weise eingesetzt werden, daß beispielsweise zunächst nur ein Kunststoffrohr eingeschoben und mit dem Heizwendelfitting verschweißt wird. Das andere Installationsbauteil bzw. die andere Armatur kann dann durch ein später noch einzubringendes Kunststoffrohr, ein in das freie Ende des Fittingrohres einschraubbares Ventil aus Metall oder ein Ventil aus Kunststoff, einen Schlauch usw. gebildet sein. Bei einer derartigen Ausgestaltung bietet es sich vorteilhaft an, wenn das Heizwendelfitting zwei unabhängig voneinander ansteuerbare Heizelemente besitzt, so daß mit dem einen Heizelement das zunächst eingebrachte Kunststoffrohr mit dem Heizwendelfitting verschweißt werden kann, wogegen das zweite Heizelement dann zum Verbinden des weiteren Installationsbauteils mit dem Heizwendelfitting dient. Selbstverständlich ist die Zahl der in dem Heizwendelfitting vorzusehenden Heizelemente hierdurch nicht festgelegt; es ist für jeden beliebigen Einsatzzweck eine entsprechende Zahl an Heizelementen möglich.As mentioned above, the present invention is not limited to the use of heating coil fittings for connecting two tubes are provided. For example, it can also be used for T-shaped heating coil fittings, designed to connect three pipes, etc. be used. Furthermore, the heating coil fitting according to the invention can also be used in such a way that, for example, initially only a plastic tube inserted and welded to the heating coil fitting. The other Installation component or the other fitting can then be replaced later plastic pipe to be inserted, a screwable into the free end of the fitting pipe Valve made of metal or a valve made of plastic, a hose, etc. be. With such a configuration, it is advantageous if the Heating coil fitting has two independently controllable heating elements, so that with the one heating element the plastic tube initially introduced the heating coil fitting can be welded, whereas the second heating element then to connect the other installation component with the heating coil fitting serves. Of course, the number to be provided in the heating coil fitting Heating elements not determined by this; it is for any purpose a corresponding number of heating elements possible.

Hinsichtlich des Verfahrens wird die vorstehende Aufgabe durch Merkmale des Anspruchs 10 gelöst. Hierbei wird mindestens ein den Kernmantel umgebender Außenmantel vorgesehen, der aus einem zumindest bei Erwärmung schrumpfenden Material hergestellt wird und der einen Innendurchmesser aufweist, welcher kleiner als der Außendurchmesser des Kernmantels ist, und daß zum Aufsetzen des Außenmantels auf den Kernmantel der Innendurchmesser des Außenmantels aufgeweitet wird. Infolge der Schrumpfeigenschaft des Materials des Außenmantels fixiert sich anschließend der Außenmantel selbstständig auf dem Kernmantel.With regard to the method, the above task is characterized by features of Claim 10 solved. In this case, at least one surrounding the core jacket Outer jacket is provided, which at least shrinks when heated Material is produced and which has an inner diameter which is smaller than the outer diameter of the core jacket, and that for mounting the Outer jacket on the core jacket the inner diameter of the outer jacket is expanded. Due to the shrinking properties of the material of the outer jacket The outer jacket then fixes itself on the core jacket.

Weitere vorteilhafte Ausgestaltungen sowie ein Ausführungsbeispiel werden nachstehend unter Bezugnahme auf die beigefügte Zeichnungsfiguren näher erläutert. Hierbei zeigt:

Figur 1
eine Teilquerschnittsansicht in Längsrichtung eines erfindungsgemäßen Heizwendelfittings;
Figur 2
eine Teilquerschnittsansicht in Längsrichtung eines weiteres Ausführungsbeispiels eines erfindungsgemäßen Fittings; und
Figur 3
eine Seitenansicht eines Heizleiters für ein Heizelement eines erfindungsgemäßen Heizwendelfittings.
Further advantageous refinements and an exemplary embodiment are explained in more detail below with reference to the accompanying drawing figures. Here shows:
Figure 1
a partial cross-sectional view in the longitudinal direction of a heating coil fitting according to the invention;
Figure 2
a partial cross-sectional view in the longitudinal direction of a further embodiment of a fitting according to the invention; and
Figure 3
a side view of a heating conductor for a heating element of a heating coil fitting according to the invention.

In den Figuren 1 und 2 ist jeweils in einem Teillängsquerschnitt ein erfindungsgemäßes Heizwendelfitting 10 wiedergegeben. Seine Mittelängs- bzw. Symmetrielängsachse M verläuft, bezogen auf Figur 1 und 2, horizontal. In den Figuren 1 und 2 sind gleiche Bauteile mit gleichen Bezugszeichen gekennzeichnet.FIGS. 1 and 2 each show a part according to the invention in a partial longitudinal cross section Heizwendelfitting 10 reproduced. Its central longitudinal or symmetrical longitudinal axis M runs horizontally, based on FIGS. 1 and 2. In the figures 1 and 2 are identical components with the same reference numerals.

Das Heizwendelfitting 10 der Figur 1 weist ein Fittingrohr 20 und ein Heizelement 30 vorzugsweise in Form einer Heizwendel auf. Die das Fittingrohr 20 definierende Rohrwand 22 umfaßt einen eine erste rohrartige Lage bildenden Kernmantel 24 und einen eine zweite rohrartige Lage bildenden Außenmantel 26, der den Kernmantel 24 konzentrisch umgibt. Hierbei liegt der Außenmantel 26 flächig an dem Kernmantel 24 an. Wie in der Figur 1 dargestellt, schließt der Außenmantel 26 mit dem Kernmantel 24 an den Stirnseiten bündig ab. Grundsätzlich besteht aber auch die Möglichkeit, daß der Außenmantel 26 eine längere oder kürzere axiale Länge besitzt als der Kernmantel 24.The heating coil fitting 10 of FIG. 1 has a fitting pipe 20 and a heating element 30 preferably in the form of a heating coil. The one defining the fitting pipe 20 Tube wall 22 comprises a core jacket 24 and forming a first tubular layer an outer jacket 26 forming a second tubular layer, which is the core jacket 24 concentrically surrounds. Here, the outer jacket 26 lies flat on the Kernmantel 24 on. As shown in Figure 1, the outer jacket 26 includes the core jacket 24 flush at the end faces. Basically, there is also the possibility that the outer jacket 26 has a longer or shorter axial length has as the core jacket 24.

Der Kernmantel 24 besteht aus einem bei Erwärmung zumindest plastifizierenden bzw. erweichenden Material, vorzugsweise aus einem thermoplastischen Kunststoff. Im Inneren des Kernmantels 24 ist der aus vorzugsweise einer Kupferlegierung hergestellte und bei diesem Ausführungsbeispiel mit rundem Querschnitt ausgestaltete Heizleiter 32 der Heizwendel 30 in der Weise angeordnet, daß er sich in der Nähe der Innenumfangswand 20a des Fittingrohres 20 bzw. des Kernmantels 24 im Inneren des Kernmantels 24 befindet. Der Heizleiter 32 ist spiralförmig gewickelt und über nicht weiter dargestellte Anschlußenden mit einer elektrischen Energiequelle verbindbar.The core jacket 24 consists of an at least plasticizing when heated or softening material, preferably made of a thermoplastic Plastic. In the interior of the core jacket 24, the core is preferably one Copper alloy manufactured and in this embodiment with a round Cross section of heating conductor 32 of heating coil 30 arranged in such a way that it is in the vicinity of the inner circumferential wall 20a of the fitting pipe 20 or Core shell 24 is located inside the core shell 24. The heating conductor 32 is spirally wound and with not shown connection ends with a electrical energy source connectable.

Wie aus der Figur 1 hervorgeht, ist der Heizleiter 32 der Heizwendel 30 in der Weise im Inneren des Kernmantels 24 angeordnet, daß zwei Heizbereiche H1, H2 und drei unbeheizte bzw. "kalte" Zonen Z1, Z2, Z3 vorhanden sind. Mit anderen Worten besitzt der Heizleiter 32 der Heizwendel 30 zwei Bereiche H1, H2, in denen jeweils elf Wicklungen vorhanden sind, wobei diese beiden Bereiche H1, H2 durch eine unbeheizte Zone Z2 voneinander in axialer Richtung des Heizwendelfittings 10 getrennt sind. An den beiden stirnseitigen Enden 20b, 20c des Fittingrohres 20 sind ebenfalls unbeheizte Zonen Z1, Z3 vorgesehen, die sich von dem jeweiligen stirnseitigen Ende 20b, 20c axial in das Innere des Fittingrohres 20 bzw. des Kernmantels 24 erstrecken.As can be seen from FIG. 1, the heating conductor 32 of the heating coil 30 is arranged in the interior of the core jacket 24 in such a way that two heating areas H 1 , H 2 and three unheated or “cold” zones Z 1 , Z 2 , Z 3 are present are. In other words, the heating conductor 32 of the heating coil 30 has two areas H 1 , H 2 , in each of which there are eleven windings, these two areas H 1 , H 2 being separated from one another in the axial direction of the heating coil fitting 10 by an unheated zone Z 2 . Unheated zones Z 1 , Z 3 are also provided on the two ends 20b, 20c of the fitting pipe 20, which zones extend axially from the respective end 20b, 20c into the interior of the fitting pipe 20 or the core shell 24.

Der Außenmantel 26 des Heizwendelfittings 10 besteht aus einem schrumpfenden Material, wie beispielsweise VPE, einem Kunststoff mit Memory-Effekt usw. Vorzugsweise zumindest bei einer Erwärmung des Außenmantels 26 durch die Heizwendel 30 schrumpft das Material des Außenmantels 26 und übt dadurch einen Druck auf den Kernmantel 24 und damit auf die beiden miteinander zu verbindenden, in der Figur 1 jedoch nicht dargestellten Rohre aus vorzugsweise thermoplastischen Kunststoff aus.The outer jacket 26 of the heating coil fitting 10 consists of a shrinking Material such as VPE, a plastic with memory effect, etc. Preferably at least when the outer jacket 26 is heated by the Heating coil 30 shrinks the material of the outer jacket 26 and thereby exercises a pressure on the core jacket 24 and thus on the two together connecting, but not shown in Figure 1, preferably made of pipes thermoplastic plastic.

Zur Herstellung des erfindungsgemäßen Heizwendelfittings 10 wird zunächst der Kernmantel 24 mit der Heizwendel 30 versehen. Anschließend wird der Außenmantel 26 auf den Kernmantel 24 aufgebracht. Hierzu weist der Außenmantel 26 einen Innendurchmesser auf, der kleiner ist als der Außendurchmesser des Kernmantels 24. Nach einem Aufweiten des Innendurchmessers des Außenmantels 26 kann der Außenmantel 26 auf die Außenumfangsfläche des Kernmantels 24 aufgeschoben werden. Infolge der Schrumpfeigenschaften des Außenmantels 26 sitzt anschließend der Außenmantel 26 fest auf dem Kernmantel 24 auf.To produce the heating coil fitting 10 according to the invention, the Provide core jacket 24 with heating coil 30. Then the outer jacket 26 applied to the core jacket 24. For this purpose, the outer jacket 26 an inner diameter that is smaller than the outer diameter of the Core sheath 24. After widening the inner diameter of the outer sheath 26, the outer jacket 26 can be on the outer peripheral surface of the core jacket 24 be postponed. Due to the shrink properties of the outer jacket 26 the outer jacket 26 then sits firmly on the core jacket 24.

In Figur 2 ist ein weiteres Ausführungsbeispiel eines erfindungsgemäßen Heizwendelfittings 10 gezeigt. Bei diesem Heizwendelfitting ist die Aufteilung in einen Kernmantel und in einen Außenmantel zum Zwecke der Verdeutlichung des weiteren Erfindungsgedankens unterblieben.In Figure 2 is another embodiment of an inventive Heater coil fittings 10 shown. This heating coil fitting is divided into a core jacket and in an outer jacket for the purpose of illustrating the no further inventive idea.

Wie aus Figur 2 ersichtlich ist, besitzt der Heizleiter 32 der Heizwendel 30 einen rechteckförmigen Querschnitt bzw. eine rechteckförmige Querschnittsfläche A, wobei der Querschnitt in einer die Mittellängsachse M des Fittingrohres 20 enthaltenden Ebene verläuft. Die Breite des rechteckförmigen Heizleiters 32, d.h. seine Länge in axialer Richtung des Fittingrohres 20 ist kleiner als seine Länge in radialer Richtung des Rohres 20. Vorzugsweise beträgt das Verhältnis zwischen der axialen Länge der Querschnittsfläche A (= Breite der Querschnittsfläche A) und der radialen Länge der Querschnittfläche A (= Höhe der Querschnittsfläche A) 2:5. Hierdurch dringt der Heizleiter 32 weitaus tiefer in das Material des Fittingrohres 20 ein, als dies bei einem Fittingrohr mit gleicher Wandstärke und einem Heizleiter mit rundem Querschnitt der Fall ist, wie ein einfacher Vergleich der Figuren 1 und 2 zeigt. Es hat sich als vorteilhaft erwiesen, wenn die radiale Ausdehnung des Heizleiters 32 bzw. die Höhe der Querschnittsfläche A wenigstens 30 % der radialen Wanddicke der Rohrwand 22 beträgt. Auf Grund des rechteckförmigen Querschnitts des Heizleiters 32 ist auch der Abstand zwischen zwei aufeinanderfolgenden Heizleiterwendeln konstant, so daß, im Gegensatz zum Stand der Technik mit einem einen kreisförmigen Querschnitt aufweisenden Heizleiter, die Zwischenbereiche zwischen zwei aufeinanderfolgenden Heizleiterwendeln gleichmäßig erwärmt werden. Der Abstand bzw. die Steigung des wendelförmigen Heizleiters 32 entspricht vorzugsweise wenigstens der Länge der radialen Ausdehnung des Heizleiters 32.As can be seen from FIG. 2, the heating conductor 32 of the heating coil 30 has one rectangular cross-section or a rectangular cross-sectional area A, the cross section in a the central longitudinal axis M of the fitting pipe 20 containing plane. The width of the rectangular heating conductor 32, i.e. its length in the axial direction of the fitting pipe 20 is less than its length in radial direction of the tube 20. Preferably, the ratio between the axial length of the cross-sectional area A (= width of the cross-sectional area A) and the radial length of cross-sectional area A (= height of cross-sectional area A) 2: 5. As a result, the heating conductor 32 penetrates much deeper into the material of the fitting pipe 20 a than this with a fitting pipe with the same wall thickness and a heating conductor with a round cross section is the case, as a simple comparison of Figures 1 and 2 shows. It has proven to be advantageous if the radial expansion of the Heizleiters 32 or the height of the cross-sectional area A at least 30% of radial wall thickness of the tube wall 22 is. Because of the rectangular The cross section of the heating conductor 32 is also the distance between two successive ones Heizleiterwendeln constant, so that, in contrast to the state of Technology with a heating conductor having a circular cross section, the Intermediate areas between two successive heating conductor coils be heated evenly. The distance or slope of the helical Heating conductor 32 preferably corresponds at least to the length of the radial one Extension of the heating conductor 32.

In Figur 3 ist eine Seitenansicht des beispielsweise aus einer Kupferlegierung hergestellten Heizleiters 32 des erfindungsgemäßen Heizwendelfittings 30 wiedergegeben. Wie daraus ersichtlich ist, ist der Heizleiter 32 in gleichmäßigen Abständen an seiner von der Innenumfangsfläche 22 des Fittingrohres 20 wegweisenden Seite mit in gleichen Abstand zueinander angeordneten Einkerbungen 34 versehen. Diese Einkerbungen 34 ermöglichen u.a. ein spiralförmiges Wickeln des Heizleiters 32 zu einer Heizwendel 30, ohne daß er hierbei reißt.In Figure 3 is a side view of, for example, made of a copper alloy produced heating conductor 32 of the heating coil fitting 30 according to the invention reproduced. As can be seen from this, the heating conductor 32 is uniform Distances on its from the inner peripheral surface 22 of the fitting pipe 20th groundbreaking side with equally spaced notches 34 provided. These notches 34 allow, inter alia, a spiral Winding the heating conductor 32 to form a heating coil 30 without tearing it.

Wie weiterhin aus Figur 2 hervorgeht, schließt bei dem erfindungsgemäßen Heizwendelfitting 10 der Heizleiter 32 der Heizwendel 30 bündig mit der Innenumfangsfläche 20a des Fittingrohres 20 ab. Aufgrund des rechteckförmigen Querschnitts des Heizleiters 32 der Heizwendel 30 wird darüber hinaus im Gegensatz zu einem Heizleiter mit rundem Querschnitt auch eine bessere Durchwärmung der beiden miteinander zu verbindenden Rohre K1, K2 erreicht, da der Heizleiter 32 mit seiner Breitseite jeweils auf den miteinander zu verbindenden Rohren "aufsteht". Demgegenüber ist bei einem Heizleiter mit einem kreisförmigen Querschnitt, wie es häufig im Stand der Technik der Fall ist, nur eine Linienberührung zwischen dem Heizleiter und den beiden miteinander zu verbindenden Rohren K1, K2 möglich.As can further be seen from FIG. 2, the invention closes Heizwendelfitting 10 of the heating conductor 32 of the heating coil 30 flush with the Inner circumferential surface 20a of the fitting pipe 20. Because of the rectangular shape Cross section of the heating conductor 32 of the heating coil 30 is also in In contrast to a heating conductor with a round cross section, a better one Warming of the two pipes K1, K2 to be connected is achieved because the heating conductor 32 with its broad side in each case on those to be connected to one another Pipes "stands up". In contrast, a heating conductor with a circular Cross section, as is often the case in the prior art, only a line contact between the heating conductor and the two pipes to be connected K1, K2 possible.

Wie dies bereits vorstehend dargelegt wurde, ist die Heizwendel 30 in dem Fittingsrohr 20, um ein Ausfließen von warmen Kunststoff aus dem Heizwendelfitting 10 zu verhindern, darin so angeordnet, daß insgesamt drei unbeheizte Zonen oder "kalte" Zonen Z1, Z2, Z3 zwischen den beiden beheizten Zonen H1, H2, die jeweils sieben Wicklungen bzw. Wendeln umfassen, vorhanden sind. Die unbeheizten Zonen Z1, Z3 erstrecken sich von den stirnseitigen Enden 20b, 20c des Fittingrohres 20 axial nach Innen. Die dritte "kalte" Zone Z2 liegt in der Mitte des Fittingrohres 20.As already explained above, the heating coil 30 is arranged in the fitting pipe 20 in order to prevent warm plastic from flowing out of the heating coil fitting 10, so that a total of three unheated zones or "cold" zones Z 1 , Z 2 , Z 3 between the two heated zones H 1 , H 2 , each comprising seven windings or coils. The unheated zones Z 1 , Z 3 extend axially inward from the front ends 20b, 20c of the fitting pipe 20. The third "cold" zone Z 2 lies in the middle of the fitting pipe 20.

Claims (10)

Heizwendelfitting zum Verbinden von wenigstens zwei Installationsbauteilen (K1, K2), von denen mindestens eines aus Kunststoff ist, mit einem Fittingrohr (20), das die wenigstens zwei miteinander zu verbindenden Installationsbauteile (K1, K2) übergreift, und mit mindestens einem in der Rohrwand (22) des Fittingrohres (20) zumindest abschnittsweise angeordneten Heizelement (30), wobei die Rohrwand (22) des Fittingrohres (20) wenigstens abschnittsweise einen inhomogenen Aufbau mit wenigstens einem ersten Material aufweist, das bei Erwärmung zumindestens plastifiziert,
dadurch gekennzeichnet, daß für den inhomogenen Aufbau der Rohrwand (22) des Fittingsrohres (20) weiterhin mindestens ein zweites Material vorgesehen ist, das bei Erwärmen einem Schrumpfvorgang unterliegt.Heating coil fitting for connecting at least two installation components (K1, K2), at least one of which is made of plastic, with a fitting pipe (20) which overlaps the at least two installation components (K1, K2) to be connected, and with at least one in the pipe wall (22) of the fitting pipe (20) at least in sections arranged heating element (30), wherein the pipe wall (22) of the fitting pipe (20) has at least in sections an inhomogeneous structure with at least a first material which at least plasticizes when heated,
characterized in that for the inhomogeneous structure of the pipe wall (22) of the fitting pipe (20) at least a second material is further provided which is subject to a shrinking process when heated. Heizwendelfitting nach Anspruch 1,
dadurch gekennzeichnet, daß das zweite Material (26) in dem ersten Material (24) eingelagert istHeizwendelfitting according to claim 1,
characterized in that the second material (26) is embedded in the first material (24) Heizwendelfitting nach Anspruch 1,
dadurch gekennzeichnet, daß die Rohrwand (22) des Fittingrohres (20) aus mindestens einer ersten Lage aus dem ersten Material (24) und wenigstens einer zweiten Lage aus dem zweiten Material (26) gebildet ist.Heizwendelfitting according to claim 1,
characterized in that the pipe wall (22) of the fitting pipe (20) is formed from at least a first layer from the first material (24) and at least a second layer from the second material (26). Heizwendelfitting nach Anspruch 3,
dadurch gekennzeichnet, daß die erste Lage aus dem ersten Material (24) von der zweiten Lage aus dem zweiten Material (26) konzentrisch umgeben ist.Heizwendelfitting according to claim 3,
characterized in that the first layer of the first material (24) is concentrically surrounded by the second layer of the second material (26). Heizwendelfitting nach einem der Ansprüche 1 bis 4,
dadurch gekennzeichnet, daß das Heizelement (30) unter Ausbildung von unbeheizten Zonen (Z1, Z2, Z3) im Inneren des Fittingrohres (20) angeordnet ist. Heating coil fitting according to one of claims 1 to 4,
characterized in that the heating element (30) is arranged to form unheated zones (Z 1 , Z 2 , Z 3 ) in the interior of the fitting pipe (20). Heizwendelfitting nach einem der Ansprüche 1 bis 5,
dadurch gekennzeichnet, daß der das Heizelement (30) bildende Heizleiter (32), bezogen auf eine die Mittellängsachse (M) des Fittingrohres (20) enthaltende Schnittebene, eine Querschnittsfläche (A) aufweist, deren Ausdehnung in Richtung der Mittellängsachse (M) des Fittingrohres (20) kleiner als in radialer Richtung, bezogen auf das Fittingrohr (20), ist.Heating coil fitting according to one of claims 1 to 5,
characterized in that the heating conductor (32) forming the heating element (30), in relation to a sectional plane containing the central longitudinal axis (M) of the fitting pipe (20), has a cross-sectional area (A), the extension of which in the direction of the central longitudinal axis (M) of the fitting pipe (20) is smaller than in the radial direction, based on the fitting pipe (20). Heizwendelfitting nach Anspruch 6,
dadurch gekennzeichnet, daß die radiale Ausdehnung des Heizleiters (32) wenigstens 30 % der radialen Wanddicke der Rohrwand (22) beträgt.Heizwendelfitting according to claim 6,
characterized in that the radial extension of the heating conductor (32) is at least 30% of the radial wall thickness of the tube wall (22). Heizwendelfitting nach Anspruch 6 oder 7,
dadurch gekennzeichnet, daß die Querschnittsfläche (A) rechteckförmig ist und daß das Verhältnis von radialer Ausdehnung zu axialer Ausdehnung der Querschnittsfläche (A) 5:2 beträgt.Heizwendelfitting according to claim 6 or 7,
characterized in that the cross-sectional area (A) is rectangular and in that the ratio of the radial extent to the axial extent of the cross-sectional area (A) is 5: 2. Heizwendelfitting nach einem der Ansprüche 1 bis 8,
dadurch gekennzeichnet, daß die Steigung des wendelförmig gewickelten Heizleiters (32) wenigstens der radialen Ausdehnung des Heizleiters (32) entspricht.Heating coil fitting according to one of claims 1 to 8,
characterized in that the slope of the helically wound heating conductor (32) corresponds at least to the radial extent of the heating conductor (32). Verfahren zum Herstellen eines Heizwendelfittings gemäß dem Oberbegriff des Anspruchs 1, bei dem mindestens ein Kernmantel hergestellt wird, in dem die Heizwendel aufgenommen ist,
dadurch gekennzeichnet, daß mindestens ein den Kernmantel aufnehmender Außenmantel vorgesehen wird, der aus einem zumindest bei Erwärmung schrumpfenden Material hergestellt ist und der einen Innendurchmesser besitzt, der kleiner ist als der Außendurchmesser des Kernmantels, und daß zum Aufsetzen des Außenmantels auf den Kernmantel der Innendurchmesser des Außenmantels aufgeweitet wird.Method for producing a heating coil fitting according to the preamble of claim 1, in which at least one core jacket is produced in which the heating coil is accommodated,
characterized in that at least one outer jacket receiving the core jacket is provided which is made of a material which shrinks at least when heated and which has an inner diameter which is smaller than the outer diameter of the core jacket, and in that the inner diameter of the outer jacket is placed on the core jacket Outer jacket is expanded.
EP99103387A 1998-02-25 1999-02-22 Heat-fusion coil fitting incorporating a shrink sleeve and a fabrication process for the same Expired - Lifetime EP0939269B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19807950A DE19807950A1 (en) 1998-02-25 1998-02-25 Heating coil fitting with shrink jacket
DE19807950 1998-02-25
US09/256,560 US6215107B1 (en) 1998-02-25 1999-02-24 Heating coil fitting with shrunk-on cover and process for same

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EP0939269A1 true EP0939269A1 (en) 1999-09-01
EP0939269B1 EP0939269B1 (en) 2004-07-28

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Publication number Priority date Publication date Assignee Title
DE10047475A1 (en) * 2000-09-21 2002-04-11 Georg Fischer Wavin Ag Subinge Welding parts made of plastic
DE102005047465A1 (en) * 2005-09-30 2007-04-05 Conti Temic Microelectronic Gmbh Joining together two plastic parts, especially car key halves, comprises passing current through a conductor on a joining surface so that the surfaces adjacent to the conductor are melted and bonded together
CA2704406A1 (en) 2010-05-19 2011-11-19 Shawcor Ltd. Casing member for forming a connection between tubular sections and use thereof for forming connections
DE102014017922B4 (en) * 2014-12-04 2021-05-12 Audi Ag Method for the component connection of a plastic component with a joining partner
EP3434454B1 (en) * 2017-07-26 2023-03-01 Georg Fischer Wavin AG Elastic electrowelding joint

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EP0585974A2 (en) * 1989-01-11 1994-03-09 Osaka Gas Co., Ltd. Electrofusion joint and hot water supply header using the same
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US3943334A (en) * 1973-03-14 1976-03-09 Von Roll Ag Heat weldable, thermoplastic fitting
FR2452048A1 (en) * 1979-03-19 1980-10-17 Von Roll Ag SLEEVE IN SYNTHETIC MATERIAL THAT CAN BE WELDED BY MEANS OF AN ELECTRICAL RESISTANCE WHOSE COILS SURROUND THE SLEEVE
US4362684A (en) * 1980-03-31 1982-12-07 George Fischer Aktiengesellschaft Process and apparatus for making a welding sleeve
US4906313A (en) * 1988-05-09 1990-03-06 R. W. Lyall & Company, Inc. Fusion weld method and assembly for forming a fusion welded joint between pipe sections
EP0585974A2 (en) * 1989-01-11 1994-03-09 Osaka Gas Co., Ltd. Electrofusion joint and hot water supply header using the same
DE3932807C1 (en) * 1989-09-30 1991-05-02 Georg Fischer Ag, Schaffhausen, Ch, Niederlassung: Georg Fischer Ag, 7700 Singen, De
GB2325501A (en) * 1997-05-22 1998-11-25 Uponor Ltd Heat fusion fitting

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US6215107B1 (en) 2001-04-10
EP0939269B1 (en) 2004-07-28

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